1. Field of the Invention
This invention relates to devices for removing contaminants from the surface of a carcass during meat processing. More particularly, this invention relates to tools that use vacuum and steam for removing such contaminants and for sanitizing the carcass.
2. Description of Related Art
During the initial processing of a carcass, contaminants can be inadvertently spread to the surface of the carcass. Such contaminants may be dirt or soil, residue from previous carcass processing steps or they may include fecal matter or other types of bacteriologically active contaminants. Before further processing, these contaminants must be removed to maintain the cleanliness of the carcass and the subsequent processing. A conventional method of removal is to excise the contaminated area from the carcass by cutting out the area with a knife.
This excision procedure is wasteful of the meat in the carcass, but more importantly, the knife used to make the removal cut can become contaminated and spread the contamination from the carcass surface deep into the meat of the carcass.
An alternative method to the excision method described above uses a tool, referred to as a "wand", that employs vacuum in combination with high temperature water and steam to loosen the contaminant from the carcass surface and suction it away for disposal. For such a system to be acceptable, the tool needs to remove the contaminant while simultaneously producing a sanitary surface on the carcass and avoiding the spread of the contaminant to other locations on the carcass. Unfortunately, current systems have been relatively unsuccessful at meeting these basic requirements.
A first problem has been with maintaining the proper sanitizing temperature of the water and steam. The vacuum system continuously draws air into the tool in the region being cleaned, and this air acts to rapidly cool the carcass surface and the hot water or hot water/steam being emitted by nozzles in the vicinity being cleaned. The placement of nozzles in prior art tools has been too far from the carcass surface to maintain the sanitizing temperature and properly sanitize the surface of the carcass.
In a tool of this type which uses a heated working fluid, such as water or steam, it is necessary to project the heated fluid against the carcass surface as the head passes over the location of the contamination. This loosens the contaminant and sanitizes the surface as it is removed by the airflow produced by the vacuum under the tool head.
At the exterior perimeter region of such tools, the heated fluid used may be pure steam. In this exterior region, the steam flow from the nozzles is in the same general direction as the flow of air. However, in the interior region and directly underneath the tool head where the bulk of the contaminant is likely to be found, the working fluid nozzles must project the heated fluid in the opposite general direction to the flow of air being drawn into the tool. The design of prior art tools, including the shape of the head and the relative positioning of the nozzles is such that they must use a relatively dense heated working fluid (with substantial weight and momentum) in the interior region in order for the heated fluid to arrive at the surface with an adequate temperature.
Accordingly, heated water or water/steam combinations, not steam alone, has been used as the working fluid in this interior region. Nonetheless, heated water is severely cooled by the reverse airflow as it transits from the inner nozzles to the surface, and many difficulties are encountered with maintaining the proper sanitizing temperatures.
The use of hot water in the interior region also has other disadvantages, as compared to steam. One is that water must be supplied to the tool, in addition to steam and vacuum. Another is that the water often is not completely removed from the surface of the carcass by the vacuum. This residue of water can quickly spread the contamination over a much larger region than was originally contaminated.
A further problem is that water cannot be heated above the boiling point, which may be only slightly above the desired sanitizing temperature, leaving very little range between the starting temperature of the water and the minimum temperature that must be maintained. A higher water flow through the nozzles may decrease the cooling effect somewhat and produce a higher temperature at the surface of the carcass, but this would seriously increase the water spread contamination problem. Combination steam and hot water nozzle systems have been only partially successful for the same reasons.
Aside from difficulties in maintaining the sanitizing temperature, previous vacuum-based systems have had problems with cleanliness resulting in the spread of contamination by the working head of the tool. During use, the tool head comes into contact with the contaminants. Unless the head is cleaned repeatedly, this can further spread the contamination. In view of the difficulties described above, vacuum based carcass cleaning systems have not been widely accepted.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a vacuum steam wand for sanitizing a carcass which uses steam and does not use hot water to avoid a contamination through the spread of water.
It is another object of the present invention to provide a vacuum steam wand for sanitizing a carcass which is self-sanitizing and continuously maintains the working end of the tool at a temperature above the desired sanitizing temperature.
It is a further object of the present invention to provide a vacuum steam wand for sanitizing a carcass which continuously washes the sides and edges of the tool at the working end with steam to remove contaminants from the tool surface, particularly in the sides and corners to avoid the spread of contamination.
A further object of the present invention is to provide a means of preventing contaminants from adhering to the tool surface and to permit easy cleaning thereof.
It is yet another object of the present invention to provides a comfortably insulated handle.
A further object of the present invention is to provide a means of monitoring the steam temperature.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.